Born on 27 August 1925 in Turin, Italy of a noble family. He studied in Turin and Rome and fought in World War II. After the war, he pursued higher studies in architecture and was a professional and academic. He later discerned his vocation to the priesthood and pursued studies in theology and philosophy at the Pontifical Gregorian University. He also studied at the Pontifical Ecclesiastical Academy and obtained a doctorate in canon law from the Pontifical Lateran University.

He was ordained a priest in Rome on 13 March 1954 at the age of 28. He continued his studies in Rome and was vice-chaplain of the University of Rome, before entering the diplomatic service of the Holy See in 1960. He served in Mexico, Japan, Kenya and then in curial positions in Rome, including as under-secretary, pro-secretary and then secretary of the Pontifical Commission for Justice and Peace.

Pope Paul VI appointed him as Pro-Nuncio in Papua New Guinea on 5 April 1977, and he was consecrated as an archbishop in St Peter's Basilica on 4 June 1977 by Jean Cardinal Villot (then Secretary of State). He was later appointed Nuncio in Honduras and Nicaragua on 25 November 1980, during the Sandanista regime; and was later made Nuncio in Uruguay on 1 April 1986, before being appointed Apostolic Delegate in Jerusalem and Palestine on 28 April 1990. He was instrumental in normalizing relations between Israel and the Holy See. He was appointed Pro-Nuncio in Cyprus in 1990, Nuncio in Israel in 1994 and then Nuncio in Italy and San Marino in 1998 before retiring in 2001.

In 2005, he designed the coat of arms of Pope Benedict XVI and was named Archpriest of the Pontifical Basilica of St Paul Outside the Walls on 31 May 2005. Pope Benedict XVI created him Cardinal in the consistory of 24 March 2006, after he was already 80 (and therefore ineligible to vote in future conclaves).